Firing-rate and rhythm control apparatus for automatic weapons

ABSTRACT

The firing-rate and rhythm control of an automatic weapon are effected electrically by means of a control circuit in which shot-counting is sensed at the weapon itself and timing is effected by a clock wavetrain generator. Means are provided to ensure firing of the correct number of shots per burst when operating the weapon both at natural firing rate and at reduced firing rate.

United States Patent 1 Mindel 1' July 31, 1973 1 1 FIRING-RATE AND RHYTHM CONTROL APPARATUS FOR AUTOMATIC WEAPONS [75] Inventor: Gunter Mindel, Dusseldorf,

[21] Appl. No.: 132,732

[52] U.S. Cl. 89/135 [51] Int. Cl. F41d 11/10 [58] Field of Search 42/1 E, 84; 89/28,

[56] References Cited UNITED STATES PATENTS 3,217,601 11/1965 Gardner 42/84 7/1969 Goodwin 89/135 7/1944 Webb 42/1 E Primary ExaminerStephen C. Bentley Attorney-Watson, Cole, Grindle & Watson [57] ABSTRACT The firing-rate and rhythm control of an automatic weapon are effected electrically by means of a control circuit in which shot-counting is sensed at the weapon itself and timing is effected by a clock wavetrain generator. Means are provided to ensure firing of the correct number of shots per burst when operating the weapon both at natural firing rate and at reduced firing rate.

'9 Claims, 3 Drawing Figures Control Equipment l LOperofing Port F" Electronic Switch 1 L F irlnq Current Button Source I PATENTED JUL3 1 I975 Fig.1

Coqtrol qulpmen A I LOperating Part V k K Firmq Current Bum, Source I f 7 9 INVl-IN'I'MR;

FHRllNG-RATE AND RHYTHM CUNTRUL APPARATUS F OR AUTOMATIC WEAPONS The invention relates to a firing-rate and rhythm control apparatus for automatic weapons which are fired by electrical control means. For example, in one known type of automatic weapon an electromagnet is provided which mechanically actuates the breech mechanism of the weapon when an energizing current is passed to it. Other constructions are however known which incorporate for example electric motors, hydraulic or pneumatic cylinders, or electrically released spring energystorage means. Generally, in electrically operating firing systems, a stored energy is released for actuating the breech mechanism.

in such automatic weapons the maximum possible sequence of shots, the natural or mechanical firing rate, is governed by the inertia of the breech mechanism. The firing rate is stated in shots per minute and depending upon calibre may be for example in the order of magnitude of 1,000 shots per minute. Automatic weapons should however be capable of firing single shots and should also offer the possibility of automatically firing sequences of shots at a rate lower than the natural rate; this form of use is designated controlled single-shot firing (cadence fire). Finally, it is also required to be able to use the automatic weapon in a predetermined rhythm." Such rhythm consists of cycles which are separated from each other by intervals; each cycle consists of bursts of fire" which are separated from each other by burst intervals or fire intervals, and each burst of fire in turn consists of a predetermined number of shots the time interval between which is determined either by the natural firing rate of the weapon or by the reduced firing rate in the case of controlled single-shot fire (cadence fire).

Since firing of the weapon is controlled by electrical means, it is possible to carry out the stated types of firing automatically by electrical means. Firing-rates and rhythm control means are known which control the various types of firing with the help of electromechanical interruptors. Such control means are used during the testing of the weapons since it is then possible to carry out objective measurements when the weapon is subjected to the severest stress (controlled single-shot fire) and when determining the thermal behavior (rhythm firing). The control means, however, also offer advantages when the weapon is in use, since they relieve the gunners of unnecessary manual and mental operations. For this purpose, however, they must be of simple and compact construction; mechanically moved parts of the control means should be avoided since they are of necessity subjected to wear and are also sensitive to dirt, atmospheric moisture and other external influencing factors.

A particular problem with control means of this kind consists in the fact that each burst of fire in a cycle should cover an accurately predetermined number of shots at each firing rate which should be adjustable irrespective of the number of shots per burst. if the number of release impulses passed to the firing magnet is predetermined, this functions to give controlled singleshot fire, since in this case the breech mechanism is locked after each shot, whereas at the natural firing rate one further shot is usually fired as a result of the inertia of the mechanical system.

The object of the invention is to provide a firing-rate and rhythm control apparatus for automatic weapons having electrically controlled firing, for example by means of an electromagnet, which apparatus operates without mechanical interruptors, even through these may be additionally provided for reasons of safety, and which ensures reliable control, in, accordance with an adjustable program, at each firing, rate, and in particular ensures that a predetermined number of shots per burst is maintained.

According to the invention, this object is achieved by means of a presettable counter for the number n of shots per burst, by means of a pulse generator for driving the counter, which pulse generator is triggered by the weapon, and by means of a switching device for switching off the control means. to terminate firing when the preset number of shots is reached. Accordingly, firing control means does not simply receive a predetermined number of release impulses (for controlled single-shot firing) or a continuous impulse of predetermined duration (for firing at a mechanical firing rate); instead, the activation of the control means is caused by the weapon itself and is used for influenc' ing a preset counter which then. only interrupts the burst when the predetermined number of shots has actually been fired. In the first place, this has the advantage that if a release impulse does not occur, the counter does not continue to count. Secondly, the pulse generator can be so fitted, on a part of the breech mechanism of the weapon for example, and can be so designed that at high firing rates the penultimate shot in a burst causes the release circuit to become nonoperative after a suitable period of delay, with the result that the sum of the electrical and mechanical delays is taken into account when releasing the shots. When the natural firing rate is selected, the counter is automatically moved one unit forward. If, for example, a forward-counting counter is used, then, when the required number of shots, for example 12, for a burst is reached, it will emit a signal which stops further firing of the weapon. When the apparatus is switched to a high firing rate (the mechanical firing rate), the counter is at the same time switched to one, so that after 11 shots it provides the stop signal. However, the remaining shot of the burst is fired as the result of the mechanical and possibly the electrical inertia of the system. The total delay caused by the inertia is known or at least measurable, so that it is possible to ascertain with accuracy which is the firing rate beyond which this advance" must become effective. In the known automatic weapons, the highest firing rate in controlled individual firing is only about half of the mechanical firing rate of the weapon, so that the advance of a shot needs to be envisaged only in the latter case.

The firing rate and rhythm control apparatus must not only safely maintain the number of shots per burst but also the intervals between the individual shots of a burst during controlled single-shot firing (first at about half the natural rate or a still lower rate), the intervals between the bursts in a cycle, and the intervals between the individual cycles ,of a rhythm. in a preferred embodiment of the invention, there is provided a timing wavetrain generator for producing the time units for these intervals. The timing generator is preferably a frequency-stabilized audio-frequency generator, for example a tuning-fork-controlled oscillator or a quartz oscillator with divider stages, and produces a fixed basic frequency. One cycle of this frequency is the smallest time unit of each of the abovementioned intervals; it is found that at a natural firing rate of 1,000 shots per minute and thus at a maximum frequency of, for example, 600 shots per minute for controlled singleshot firing, the smallest time unit of the interval is (600 60) seconds, i.e., 100 msec. A time unit of 20 msec., corresponding to an audio-frequency of 50 cycles/- second has proved to be small enough also to enable fine stepping in the rate of the controlled single-shot firing to be provided.

The choice of the particular interval time is made in very much the same way as that of th'e'number of shots per burst by providing a counter for each interval, which counter is preset by the associated selector switch and is counted down toward zero by means of the impulses from the clock generator (reverse counters being used) or is up-counted until the predetermined final count position is reached (in the case of forward counters). It will be understood that if required, a frequency divider can be provided for the audio-frequency; the scale reading of the selector switches gives the actual interval time for the burst intervals and cycle intervals, whereas the scale of the firing rate selector switch gives the number of shots per minute.

By way of example, the following program (rhythm) I is considered: Audio-frequency 50 cycles/second corresponds to a time unit of 20 msec.

Firing rate 300'shots per minute Burst 20 shots Cycle 3 bursts at intervals of 5 seconds Rhythm 4 cycles at intervals of 20 seconds Three hundred shots per minute corresponds to a time interval between two successive shots in each burst of 60 :300 seconds or 200 msec. The counter associated with the firing rate set-means is therefore preset to the counting position and this counting position appears on the scale of the selector switch as firing rate 300 min.

The counter corresponds for the number of shots per burst is preset to to correspond with the reading on the scale of the corresponding selector switch. The figure on the counter does not need to be reduced for this low firing rate. The counter for the intervals between bursts has to be set to 250 (Sseconds: 2O 10 seconds). The counter for the intervals between cycles has to be set to 20 20 l0 1,000. Corresponding counters are of course provided for counting the number of bursts per cycle and the number of cycles per rhythm; the burst counter is stepped up when the end position of the shot-per-burst counter is reached, and the cycle counter is stepped up when the end position of the burst counter is reached. When the cycle counter reaches its end counting position, the rhythm, i.e., the program is complete. At that point the above sequence is automatically repeated.

The impulse generator provided on the weapon can also be used for increasing safety in the use of the weapon both in testing and in battle or on manoeuvers. According to a further improvement of the invention control switching means is associated with the impulse generator, which means interrupts the circuit for operating or simply the circuit for the firing magnet when the impulse generator, upon release of the shot, generates no impulse because the weapon, ammunition or control apparatus has become defective. Even when the impulse generator itself is damaged, the circuit is interrupted in this manner so that no shots exceeding thenumber determined by the envisaged program are involuntarily fired.

Since, using the control apparatus of the invention, each selected rhythm proceeds automatically and the individual actions are in any case counted, the counter setting for the bursts, the cycles and the number of shots fired can also be indicated visually as a whole, for example, by means of a summation counter supplied with signals from the impulse generator. This counter can also incorporate a pre'se'tting' corresponding, fore'x ample, to the ammunition stock, and can be counted down toward zero by the signals from the impulse generator, so that the particular position of the counter indicates the quantity of ammunition still present.

The invention will now be described in more detail by reference to the accompanying drawings, in which FIG. 1 shows schematically the arrangement of the control apparatus of the invention and how it is connected to the weapon;

FIG. 2 shows the block circuit diagram of the apparatus of FIG. 1; and

FIG. 3 provides graphs illustrating the time sequence of a number of successive shots and the corresponding signals of the apparatus for the natural firing rate.

The weapon 1, an automatic gun, schematically illustrated in FIG. 1 is fired by means of an electromagnet 2, the movement of the armature of which is transmitted through a linkage system 3 to the firing lever. The electromagnet 2 is energized through an electronic switch 4 which in known manner can take the form of a thyristor switch or a power transistor. When the switch 4 remains closed, the weapon fires at its natural firing rate. Provision is made for the firing magnet to be energized within the shortest possible time, i.e., a few micro-seconds; when the electromagnet circuit contains a thyristor, a switch-off thyristor is provided for this purpose. As explained above, a well-defined time at which switch-off occurs is important for the operation of the control apparatus of the invention.

The switch 4 is actuated by control equipment 5, parts of which may optionally be accommodated in a mechanically separate operating part 6 connected to the control apparatus 5 by cables. This operating part contains a firing button 7. When depressed, the firing button 7 also closes the energizing circuit of a delayedrelease power relay, the contacts of which are in series with the energizing coil of the firing magnet 2 and its electronic power switch 4. This ensures that in the event of the switch 4 breaking down, the weapon can be rendered nonoperative by releasing the firing button 7. The delay is provided to'enable the firing magnet in the normal case to be switched off by the electronic power switch 4 and only switched off by the relay in the event of malfunction. Only the switch 4 ensures that switching off occurs at the required well-defined moment. The current source 9 is indicated schematically.

An impulse generator 8 is connected to the weapon to transmit signals to the control apparatus 5. When designing the impulse transmitter, it has to be taken into consideration that it operates in a practically intertialess manner as regards firing frequency, and must be rigid and unaffected by vibrations. In the present embodiment, a semi-conductor component responsive to changes in magnetic flux is used as a detector. The detector is arranged in a fixed position in relation to a likewise fixed permanent magnet, and interference with the magnetic field of the magnet by parts of the weapon moving past it produces a signal of sufficient magnitude at the terminals of the detector. In order to obtain a steep front edge flank of the impulse, use is made of a component of the weapon that reaches a high mechanical speed, and in the illustrated embodiment, the clamping cam of the breech mechanism 24 is utilized. The arrangement of the permanent magnet and of the semi-conductor component (here, of the design commercially available under the trade name Feldplatte) is such that the impulse is generated a few milli-seconds before the shot. A pulse shaping circuit is connected to the output terminals of the impulse transmitter for extending the pulse duration of the impulse (see FIG. 2), the extension of the time being sufficient to render ineffective any peaks, rising above the threshold level of the circuit 10 and possibly caused by vibration of the weapon of firing, and the impulse which occurs in response to the stroke of the clamping cam of the breech mechanism does not affect the operation either, (impulses 31 and 33 in FIG. 3, with interference impulses 32 between them).

The extended impulse 34 at the output of the pulse shaping circuit 10, plotted vs. time, is shown in FIG. 3. It will be obvious to one skilled in the art that the circuit 10 also causes amplification and formation of the impulse; impedance matching also is provided.

Instead of a magnetically operated impulse generator, use can also be made of impulse generators which operate capacitively or photoelectrically; the arrangement described has, however, proved successful in practice.

The impulses 34 pass through an amplifier 11 to mechanical counting units 27 and 28 for counting the total number of shots fired or the ammunition stock still available; one counter is provided in the control appa ratus 5 and one in the operating part 6.

The control apparatus also includes a clock wavetrain generator 12 consisting of a tuning-forkcontrolled audio-frequency oscillator, oscillating at l kilocycle. The output of this generator is connected to a divider stage having a 20 l division ratio, so that a frequency of 50 cycles/second appears at the output of generator 12. This frequency, having a cycle duration of 20 msec., is passed to interval time counters l3 having selector switches 14 for setting the interval between bursts and the interval between cycles, and to a firing rate time counter 19 with associated selector switch 20. The mode of operation of these units has been explained in detail above; the details of their construction do not form any part of the present invention.

A shot counter 17 is provided for'receiving the output signals from the circuit 10. A selector switch 18 which, as explained above, selects the number of shots per burst, is connected to counter 17.

A burst counter is provided, setting of which is achieved by means of a selector switch 16. Further visual indicating means 25 is provided. There is also provided a cycle counter 21 with which are associated a selector switch 22 and visual indicating means 26. The manner in which the lastmentioned components cooperate has been explained in the introduction.

Finally, an operating panel 50 is shown separately. It is firstly provided with a key-actuated main switch 29 marked with the positions firing blocked (current supply interrupted, key withdrawn), cancel (all counters are returned to their starting positions) and ready to fire. In the last-named position of the switch, firing can be started by depressing the button 7. The type of fire is determined by the position of the fire-type selector switch 23 marked with the positions single-shot fire (depression of the button 7 releases only one shot and the next shot follows only after the button has been released and depressed again), continuous fire (depression of the button starts continuous fire at the natural firing rate until the button 7 is released again), reduced firing rate (the same as for continuous firing but at the reduced rate as selected by the switch 20), rhythmic continuous fire (the same as for continuous firing but in a rhythm in accordance with the setting of the switches 14, 16, 18 and 22) and finally, rhythmic fire at reduced lfiring rate (the same as rhythmic continuous fire, but at a rate in accordance with the position of the switch 20). The button 7 in the control apparatus is connected in parallel with a corresponding firing button in the operating part 6; the panel 50 can be fitted with a changeover switch so as to transfer operation to the operating part which expediently likewise comprises an additional safety switch.

FIG. 3 illustrates the conditions at the end of a burst when firing at a natural rate R d. The following curves are plotted vs. time:

30 barrel-recoil distance 40 distance traveled by the clamping cam of the breech mechanism 42 signal from the impulse generator 44 signal at the output of the extending circuit 10, and

35 current through the energizing solenoid of the firing magnet.

Shortly before reaching the point at which it turns, the clamping cam of the breech mechanism passes the impulse generator 8 (point 36) and releases the signal 42. During the forward movement (impulse peak 31) as well as during the return movement (impulse peak 33), the triggering level 43 of the circuit 10 is passed; the interference impulses 32 which occur when the shot itself is released, no longer affect the extending circuit, which for example can be constituted as a mono-stable multi-vibrator with a preselectable impulse duration. The duration of the output signal 34 produced is so adjusted that it terminates roughly midway between the (n-1)" and the n' shot, n being the number of shots per burst. At the time of occurrence of the rear edge flank of the output impulse 34 of the circuit 10 which is in fact the moment at which the weapon is mechanically released for the n' shot, the firing magnet 2 ceases to pass current.

This "mechanicaP release is due to the fact that the inertia of all the mechanically moved parts (e.g., the armature of the firing magnet, the transmission linkage and the part of the breech mechanism) introduces a time delay approximately [00 msec., i.e., somewhat more than the interval between two succesisve shots at the natural firing rate of 1,000 shots per minute. This delay is also dependent upon such operating conditions as temperature, lubrication, etc., and can vary by approximately 30 msec. When the firing magnet is switched off at the stated moment, a further shot is thus reliably released when firing at the natural rate. In the case of controlled single-shot fire however, the breech mechanism is mechanically locked after each shot. The

time-constant for the release of the firing magnet is set to the lowest possible value since its tolerance is added to the mechanicalv time-constant of the breech mechanismr The energization time of the firing magnet is firmly set at roughly 50 msec., in the case of controlled single-shot fire.

I claim:

1. A firing-rate and rhythm control apparatus for the control of an automatic weapon with electrically governed firing means, comprising in combination:

a. a weapon-actuated impulse generator which produces impulses in response to the firing of shots by the weapon,

' b. a presettable impulse counter which is operatively connected to said impulse generator and which counts said impulses,

c. a firing control switching device which is operatively connected both to said impulse counter and to said firing means, and which is operated by said counter thereby stopping the action of said firing means at the end of a burst of a predetermined number of shots as defined by setting means operatively connected to said impulse counter,

. d. interval control means controlling inter-burst and inter-cycle intervals,

e. rate control means controlling the rate of controlled single shot firing, and

f. a clock wavetrain generator having its output connectedto said interval control means and said rate control means.

2. Apparatus as claimed in claim 1 wherein said impulse generator-is actuated by movement of the breech mechanism of the weapon.

3. Apparatus as claimed in claim 1 wherein there is pulse counter a pulse-shaping circuit with time constants such that the output pulse therefrom lasts for a longer time than is occupied by spurious impulses caused at said impulse generator due to vibration of the weapon during firing of the shot and due to recoil of the breech parts.

4. Apparatus as claimed in claim 1 comprising presettable'counters connected to said clock wavetrain generator and receiving therefrom pulses representing the number of clock units in the selected inter-burst and inter-cycle intervals.

5. Apparatus as claimed in claim 1 comprising a presettable counter connected to said clock wavetrain generator and receiving therefrom pulses representing the number of clock time units in the interval between successive shots.

6. Apparatus as claimed in claim 1 wherein said clock wavetrain generator comprises a frequency stabilized audiofrequency oscillator having its output connected to frequency divider circuit means.

7. Apparatus as claimed in claim 4 wherein said oscillator is tuning-fork controlled.

8. Apparatus as claimedrin claim 1 incorporating visual display counter means for indicating the usage of ammunition.

9. Apparatus as claimed in claim 1 incorporating a powerrelay in series with said firing control switching device, said relay being linkedto a firing button for closure only when said firing button is depressed.

' UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No- 3 748, 960 Dated July 31, 1973 lnvent fl Gunter Mindel It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

On the Title page of the patent, the following information should be added: Foreiqn Application Prioritv Data Apr. 17, 1970- Germany.. HP 20 18 620.3

Signed and sealed this 5th day of March 1 97 L (SEAL) Attest:

' EDWARD M.FLETC ;JR; MARSHALL NN Attesting Officer cQmmissioner f Patents. 7

"ORM PO-IOSO (10-69) USCOMM-DC 60376-P69 t u.s. GOVEFNMENT PRINTING OFFICE IBQ o-aes-as.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 7.48, 960 Dated July 31 1973 Invent Gunter Mindel It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the Title page of the patent, the following information should be added: Foreign Application Priority Data Apr, 17, 1970 Germany.. ..P 20 18' 620.3

Signed and sealed this 5th day of March l 97l (SEAL) Attest EDWARD M .FLETCH JR MARSHALL DANN Attesting Officer Commissioner of Patents.

ORM Po-1oso (10-69) USCOMM-DC 60376-P69 i 0.5. GOVEBNMENT PRINTING OFFICE: 199 O-366-384, l) 

1. A firing-rate and rhythm control apparatus for the control of an automatic weapon with electrically governed firing means, comprising in combination: a. a weapon-actuated impulse generator which produces impulses in response to the firing of shots by the weapon, b. a presettable impulse counter which is operatively connected to said impulse generator and which counts said impulses, c. a firing control switching device which is operatively connected both to said impulse counter and to said firing means, and which is operated by said counter thereby stopping the action of said firing means at the end of a burst of a predetermined number of shots as defined by setting means operatively connected to said impulse counter, d. interval control means controlling inter-burst and intercycle intervals, e. rate control means controlling the rate of controlled single shot firing, and f. a clock wavetrain generator having its output connected to said interval control means and said rate control means.
 2. Apparatus as claimed in claim 1 wherein said impulse generator is actuated by movement of the breech mechanism of the weapon.
 3. Apparatus as claimed in claim 1 wherein there is connected between said impulse generator and said impulse counter a pulse-shaping circuit with time constants such that the output pulse therefrom lasts for a longer time than is occupied by spurious impulses caused at said impulse generator due to vibration of the weapon during firing of the shot and due to recoil of the breech parts.
 4. Apparatus as claimed in claim 1 comprising presettable counters connected to said clock wavetrain generator and receiving therefrom pulses representing the number of clock units in the selected inter-burst and inter-cycle intervals.
 5. Apparatus as claimed in claim 1 comprising a presettable counter connected to said clock wavetrain generator and receiving therefrom pulses representing the number of clock time units in the interval between successive shots.
 6. Apparatus as claimed in claim 1 wherein said clock wavetrain generator comprises a frequency stabilized audiofrequency oscillator having its output connected to frequency divider circuit means.
 7. Apparatus as claimed in claim 4 wherein said oscillator is tuning-fork controlled.
 8. Apparatus as claimed in claim 1 incorporating visual display counter means for indicating the usage of ammunition.
 9. Apparatus as claimed in claim 1 incorporating a power relay in series with said firing control switching device, said relay being linked to a firing button for closure only when said firing button is depressed. 